As flat panel display components liquid crystal display (LCD) devices have been primarily used for mobile phones and personal digital assistants. Organic electro-luminescence (EL) display devices have been experimentally installed in such compact electronic equipment because the EL display devices have significant advantages of faster response speeds and wider viewing angles than the LCD devices.
Some folding type mobile phones and handy electronic equipment are provided with a flat panel display device for displaying images in both their folded and unfolded states, i.e., for displaying images on their front and back panels. They are, however, thicker in thickness than those with a one-sided display device. It is quite important for mobile phone, handy electronic equipment, etc. to be sufficiently thin even though they have such a display device as described above.